The present invention relates to a pad which can be used for example for application of heat or cooling to a body part.
The application of heat or cooling is a well known therapy and despite its simplicity is highly effective in alleviating pain and providing healing of various maladies.
Various proposals for pads have been made in the patent literature and various products are currently available. One current product which is widely used for this purpose comprises a fabric cover which contains granules of a heat absorbing particulate material formed from a suitable plastics material. This product is generally heated by placing the product in boiling water which communicates the heat from the water to the plastics filling material which has a sufficiently high specific heat to retain the heat applied for significant period of time. However boiling of the product is of course inconvenient and messy and results in a product which is dripping with boiling water and accordingly is difficult to handle. In addition this product is not suitable for freezing. The application of cold therapy is generally carried out by a separate product provided by a freezer pack which is simply an impermeable plastics layer containing a freezable liquid such as water, mixture of water and alcohol or other materials. This product again is difficult to handle. In both cases the products are relatively expensive and are prone to failure.
The heating therapy pad described above is divided into pockets or compartments which are rectangular and formed by stitch lines transversely to the length of the pad and longitudinally of the pad thus defining a plurality of pockets of rows and columns.
The patent literature describes various different styles of therapy pad containing various different materials.
Canadian patent 551,460 (Jensen) discloses a pad formed by rows and columns of compartments within which is provided a relatively small amount of a water insoluable hydro-philic inorganic material possessing the ability to absorb and retain an amount of water equal to at least four times and preferably ten times its volume. One example of such a material is Bentonite which is provided in the form of a stiff paste like consistency holding large quantities of water. This product is unsatisfactory in that it is messy to handle when wet and also difficult or impossible to dry so that it cannot be maintained in a hygenic condition and needs the application of fungicide.
Canadian patent 066,953 (Cheney) discloses a similar product but in this case it uses pulverized soap stone which is similar in form to talcum powder. This product clearly states that the material cannot be moistened or wetted since any moistening or soaking with medicinal fluids would destroy the article as a warming pad. The dry powder is of course difficult to contain and will tend to escape from any porous or water permeable cover.
German application 3730039 (Leyerer) discloses a cushion for hot or cold treatment of patients which is made of a cover with a filling of a heat storage material such as granules which are contained in cubicle chambers into which the cushion has been subdivided. The preferred material for the covers is polyurethane and for the filling a two component silicone rubber with sand or metal granules. The covering is therefore not water permeable and there is no intention to wetten or moisten the filler material.